R1:2bfa0e087e00

Improve consistency and Harbormaster integration of Diffusion

Summary:
Ref T9123. Two major Harbormaster-related UI changes in Diffusion:

- Tags table now shows tag build status.
- Branches table now shows branch build status.

Then some minor consistency / qualtiy of life changes:

- Picked a nicer looking "history" icon?
- Branches table now uses the same "history" icon as other tables.
- Tags table now has a "history" link.
- Browse table now has a "history" link.
- Dates now use more…